ABSTRACT This Phase II SBIR proposal submitted by Potluck LLC (Philadelphia, PA) requests funds to expand and rigorously test over 2 years an online social engagement platform (OneClick) for adults aged 65-85, including those with mild cognitive impairment (MCI). The long-term goal is to benefit health outcomes, such as survival and the mitigation of dementia, which are affected by social engagement or lack thereof. Older adults are at risk of social isolation, and therefore, negative health and quality-of-life outcomes. The existing OneClick platform connects people in different locations over shared interests in a live, small-group, video conversation. In distinct contrast to existing social media and online chat, dating, or meet-up apps, OneClick connects people online for in-depth, meaningful conversation on topics they are passionate about. No exchange of private information or physical meeting is required. Our prior research has shown older adults with and without MCI are interested in and will use computer technology and internet for personal enjoyment; however, they have unique socialization needs and technology design requirements that are rarely accommodated. In collaboration with experts in human factors, aging, and cognitive decline at the University of Illinois Urbana-Champaign, we tested and redesigned the OneClick platform in our Phase I SBIR to establish feasibility, usability, and social engagement benefits for older adults with and without MCI. In Phase II, the same team in partnership with Home- and Community-Based Organizations (HCBOs) proposes to establish OneClick?s efficacy, scalability, and market readiness. In Aim 1A, the OneClick platform, intervention content, and implementation protocols will be finalized based on Phase I learnings. This will prepare for Aim 1B, a 12-week randomized controlled trial to rigorously assess efficacy of the OneClick intervention; 120 older adults with and without MCI (60 each) will be randomized to the OneClick intervention group or the Wait-listed control group. The intervention group will use OneClick for 12 weeks, while the Wait-listed control group will receive no intervention. Both groups will complete assessments at week 6 and week 12. Subsequently, participants in the Wait-listed control group will then start using OneClick for 12 weeks of intervention, with assessments after 6 and 12 weeks. Pre-post assessments will determine effects on social engagement, quality of life, acceptance, and subjective stress. In Aim 2A, the team will partner with HCBOs to develop an online dashboard for OneClick Intervention implementation and program evaluation. This will prepare for Aim 2B, which will assess scalability by evaluating whether OneClick can be readily implemented by an HCBO to support social engagement among independently living older adults with and without MCI affiliated with their organization. The deliverable is a rigorously designed social engagement technology and program tailored to the needs, abilities, and interests of older adults with and without MCI, and the HCBOs that serve them. Upon completion of this work, OneClick will be ready for commercialization around the U.S.